Converting a TextView->Bitmap->ImageView, and nothing's showing up

Question

I started a test project just to get this down. No changes to main.xml. I want to create a widget-sized ImageView (80x100) that contains a Bitmap converted from a TextView. Yes, that sounds very roundabout but this is just for testing; in the end I want the ImageView to have a background image and multiple TextViews. I'm not sure exactly what I'm doing wrong, but nothing is being pushed to the screen.

Is it a problem with declaring the TextView/ImageView and passing it "this" in the constructor? Is it a problem with my layoutParams? Here is the code:

package com.doaf.testproject;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class TestProject extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        TextView tv = new TextView(this);
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(80, 100);
        tv.setLayoutParams(layoutParams);
        tv.setText("testing 1 2 3");
        tv.setTextColor(0xFFFFFF);
        tv.setBackgroundColor(0x555555);

        Bitmap testB;
        testB = loadBitmapFromView(tv);

        ImageView iv = new ImageView(this);
        iv.setLayoutParams(layoutParams);
        iv.setBackgroundColor(0x555555);
        iv.setImageBitmap(testB);

        setContentView(iv);
    }

    public static Bitmap loadBitmapFromView(View v) {
        Bitmap b = Bitmap.createBitmap(80, 100, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(b);
        v.layout(0, 0, 80, 100);
        v.draw(c);
        return b;
    }
}

Thanks for any help you can provide. I'm relatively new to Android, and pretty lost with this one.

@Tilsan The Fighter: I plan on using a custom layout. The end intent is to generate a LinearLayout made up of an optional background image and a few TextViews, then export that LinearLayout to a Bitmap and then to the background of a widget (ImageView?). — Rockmaninoff, Nov 12 '10 at 18:05

score 8 · Accepted Answer · answered Nov 12 '10 at 21:37

I believe its taking up the whole screen because you don't have a container such as a Linear Layout which then contains an ImageView with layout constraints, so the ImageView expands to fill the available screen. Try this:

@Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        TextView tv = new TextView(this);
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(80, 100);
        tv.setLayoutParams(layoutParams);
        tv.setText("testing 1 2 3");
        tv.setTextColor(Color.BLACK);
        tv.setBackgroundColor(Color.TRANSPARENT);

        Bitmap testB;

        testB = Bitmap.createBitmap(80, 100, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(testB);
        tv.layout(0, 0, 80, 100);
        tv.draw(c);

        ImageView iv = (ImageView)findViewById(R.id.menuIcon);
        iv.setLayoutParams(layoutParams);
        iv.setBackgroundColor(Color.GRAY);
        iv.setImageBitmap(testB);
        iv.setMaxHeight(80);
        iv.setMaxWidth(80);
    }

And in your main.xml file:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

    <ImageView android:id="@+id/menuIcon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />


</LinearLayout>

I'm not sure what you want to achieve, but I'm sure there are more efficient ways of approaching it.

score 1 · Answer 2 · answered Nov 12 '10 at 18:14

Quick modification of the code, try this and see if it's what you want to archieve:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    TextView tv = new TextView(this);
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(80, 100);
    tv.setLayoutParams(layoutParams);
    tv.setText("testing 1 2 3");
    tv.setTextColor(Color.BLACK);
    tv.setBackgroundColor(Color.TRANSPARENT);

    Bitmap testB;

    testB = Bitmap.createBitmap(80, 100, Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(testB);
    tv.layout(0, 0, 80, 100);
    tv.draw(c);

    ImageView iv = new ImageView(this);
    iv.setLayoutParams(layoutParams);
    iv.setBackgroundColor(Color.GRAY);
    iv.setImageBitmap(testB);

    setContentView(iv);
}

Hi Mike, This is definitely a step in the right direction. The background and text are rendering, but they fill up the entire screen. Could you explain why this specific code works and mine didn't (trying to learn here), and maybe why it might be filling the screen? My hunch is that it has to do with the layoutParams...or perhaps iv needs to be placed inside a Layout to prevent it from filling the screen. Thanks! — Rockmaninoff, Nov 12 '10 at 18:19

score 1 · Answer 3 · answered Nov 13 '10 at 01:11

1

Your TextView needs to be measured (call measure()) and laid out (call layout()) before you can draw it. You are doing neither.

answered Nov 13 '10 at 01:11

Romain Guy

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Converting a TextView->Bitmap->ImageView, and nothing's showing up

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